The Batu Islands are an archipelago of Indonesia

Indonesia

Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...

 located in the Indian Ocean

Indian Ocean

The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...

 off the west coast of Sumatra

Sumatra

Sumatra is an island in western Indonesia, westernmost of the Sunda Islands. It is the largest island entirely in Indonesia , and the sixth largest island in the world at 473,481 km2 with a population of 50,365,538...

, between Nias

Nias

Nīas is an island off the western coast of Sumatra, Indonesia. Nias is also the name of the archipelago, containing the Hinako archipelago....

 and Siberut

Siberut

Siberut is the largest and northernmost of the Mentawai Islands, lying 150 kilometres west of Sumatra in the Indian Ocean. A part of Indonesia, the island is the most important home for the Mentawai people. The western half of the island was set aside as the Siberut National Park in 1993...

. The three primary islands, of approximately equal size, are Pini, Tanahmasa, and Tanahbala. There are forty-eight smaller islands, of which less than half are inhabited. The islands are governed as a part of North Sumatra

North Sumatra

North Sumatra is a province of Indonesia on the Sumatra island. Its capital is Medan. It is the most populous Indonesian province outside of Java. It is slightly larger than Sri Lanka in area.- Geography and population :...

 province. In Indonesian

Indonesian language

Indonesian is the official language of Indonesia. Indonesian is a normative form of the Riau Islands dialect of Malay, an Austronesian language which has been used as a lingua franca in the Indonesian archipelago for centuries....

 and Malay

Malay language

Malay is a major language of the Austronesian family. It is the official language of Malaysia , Indonesia , Brunei and Singapore...

, batu means rock or stone.

The people of the Batu Islands have had substantial interaction with the populations of Nias, to the north. The islands have occasionally been a destination for slaves

Slavery

Slavery is a system under which people are treated as property to be bought and sold, and are forced to work. Slaves can be held against their will from the time of their capture, purchase or birth, and deprived of the right to leave, to refuse to work, or to demand compensation...

 who escaped from Nias, and in the past decade have become a destination for surfing boat charters from Padang

Padang, Indonesia

Padang is the capital and largest city of West Sumatra, Indonesia. It is located on the western coast of Sumatra at . It has an area of and a population of over 833,000 people at the 2010 Census.-History:...

, on the Sumatran mainland.

The equator

Equator

An equator is the intersection of a sphere's surface with the plane perpendicular to the sphere's axis of rotation and containing the sphere's center of mass....

passes through the archipelago, north of Tanahmasa and south of Pini.